Process of producing aromatic hydrocarbons from olefins



May 20, 12941. A. s. RAMAGE PROCESS OF PRODUCING AROMATIC HYDROGAHBONS FROM OLEFINS Filed Jue '7. 19:57

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WNOZHMDG @www 944,5 @vtm/MM35 Patented May 20, 1941 PROCESS F PRUDUCING AROMATIC HYDROCARBONS FROM OLEFINS Alexander S. Ramage, Detroit, Mich., assignor to Coals and Chemicals, Limited, Los Angeles, Calif., a corporation of Nevada Application June 7-, 1937, Serial No. 146,895

2 Claims.

This invention relates to a process of production aromatic hydrocarbons from petroleum oils, and more particularly to conversion of the parainic hydrocarbons of petroleum to olenic compounds, and then converting the oleflnic compounds, as well as any olens originally present in the petroleum, into hydrocarbons of the aromatic series.

One of the objects of lthe invention is to increase materially the proportion of compounds of the aromatic series recovered from petroleum. A further object is to provide such a process which will produce a gaseous product suitable for use, with a minimum of treatment, as an illuminating gas for use by the general public, such gas having a high heating value and a rate of ame propagation below the maximum rate set as permissible for such use. Still further objects are to provide such a process which can be economically carried out, which utilizes simple apparatus, and which can be readily controlled,

In U. S. Letters Patent No. 1,224,787, issued to me May 1, 1917, there is described a process of transforming mineral oils to convert the paraiiin components into olens components, to con.- vert the olens into terpenes, and to convert the terpenes into aromatic hydrocarbons, by passing the oils in the vapor state over a reducible oxide,

l the ttemperature being between 580 C. and 750 and thenA passing such olenic gases and vapors,

mixed with carbon monoxide and a small quantity of steam, througha second converter, in the tubes of which they are -contacted with finely.

divided iron, at a pressure approximately equal to atmospheric pressure, and at a temperature between 1100 F. and v1300 F., to convert such 1,224,787, the oil, after the asphaltic content has been removed in any suitable manner, is vaporized in a pipe still to approximately 800 F. and passed through an expander into` a converter. The vapors, consisting largely of compounds of the parain series up to approximately hexadecane, that is, having up to sixteen carbon atoms, are passed at a temperature of approximately 800 F. into a converter in which they are contacted with a reducible oxide, preferably ferric oxide, to convert such paraflins in'to the corresponding olen compounds. As described in such patent the ferrie oxideis maintained at a temperature between about 1075* F. and 1375? F., being regulated in accordance with the boiling point of the hydrocarbon to be converted. For example, an oxide temperature range between 1075 F. and 1150 F. is preferably used for con- Version of paraiiinic hydrocarbons having boiling points between 300 F. and 400 F. 'Ihe oxide is heated electrically, or otherwise, in such a way that its temperature may be readily and accurately controlled, and it has been found that, with `suitable increase or decrease of the oxide temperature to suit the increasing boiling point of the predominating hydrocarbonvpassing through the converter, a reaction product is obtained which is substantially free of hydrocarbons of the paraiiin series, and which consists predominantly of hydrocarbons of the oleiin series. In carrying out the present invention the steps outlined aboveare carried out in accordance with the .teaching of U. S. 1,224,787, to convert; the pararinic hydrocarbons predominantlyto olefins,

oleiinic hydrocarbons to hydrocarbons of the aromatic series and low boiling alcohols, particularly methanol.

The accompanying drawing is a diagrammatic representation of the essential parts of an apparatus for carrying out the process, showing the direction of ow of the various gases, vapors and liquids, by which the hydrocarbons, predominantly olens, produced from parafnic hydrocarbons by the method and apparatus described and shown in my U, S. Patent No. 1,224,787, are converted into hydrocarbons of the aromatic series and low boiling alcohols, particularly methanol.

As described in said U. S. Letters Patent No.

aiinic hydrocarbons predominantly to olens.'

Such resultantvvapors of hydrocarbons of the olen series are further treated-by the apparatus indicated, and in the manner indicated, in the drawing forminga part of this application, by .being mixed with steam, the steam being in amount equal to about 10% to 15% of the vapors, and with a volume of carbon monoxide approximately equal to the combined volume of vapors and steam, and the mixture is passed through a second converter in which it is intimately contacted with finely divided iron particles, preferably spongy iron or iron in the form of iron turnings, or wool, and heated to a temperature between 1100 F. and 1300o F. It has been found that a temperature of approximately 1200 F. is preferable, and the pressure can be only slightly above atmospheric pressure. It will be under. stood that the pressure is varied to regulate the rate of passage of the mixed vapors through the converter. With tubes three inches in diameter and thirty feet long a rate of flow such as results from vaporizing ten gallons of oil per tube per hour has been found to be preferable. While the reaction will occur at atmospheric pressure, higher pressures can be used in practice in order to utilize a converter of smaller construction. In the converter 'the olenic hydrocarbons, upon contact with the iron particles, are converted into hydrocarbons of the aromatic series and the low boiling alcohols, particularly methanol, and the resulting gases contain from 30% to 40% of olefinic gases together with methane and excess of carbon monoxide (CO).

It is believed that the conversion of the olenic hydrocarbons to aromatic compounds is due to the decomposition of the steam by the iron to form nascent hydrogen and ferrous oxide (FeO) and their reaction with the hydrocarbon compounds to form compounds having successively less hydrogen content, together with nascent hydrogen which forms formaldehyde and methanol with the carbon monoxide, as indicated in the following. in which nascent hydrogen is indicated as gz:

Fe-l-OHFFeOH- lg (nascent) Thus the co is hydrogenad to cHoH (methfor illuminating gas of low flame anol) by the nascent hydrogen and the CnH2n+z (parafiins) are dehydrogenated to CHzn4 4(aromatics). In each instance it will be noted that it is assumed that the iron again decomposes the water to form FeO and nascent hydrogen and that the eifect under rthe conditions stated is to convert the hydrocarbon compound to one having two less hydrogen atoms and to convert the CO to CHzO (formaldehyde) which is similarly converted to CHaOH (methanol).

The vapors from the second converter are purified and condensed in the usual manner to provide a high yield of benzol, toluol, xylol mixo June 30, 1931, mainly in that in the method of the present application no hydrogen is mixed with the carbon monoxide and the oleiin hydrocarbons treated are not only those having five or less carbon atoms but vapor mixtures containing olens of still greater molecular weight such as those which may be formed in the first converter from paralin ,vapors containing undecane and dodecane in considerable quantities and up to and including hexadccane and heptadecane, that is, formed from paralns having boiling points up to 500D F. to 600 F., provided that the amount of steam is increased up to 30% of steam, in accordance with an increase in the number of f carbon atoms 'inthe predominating hydrocarbons present. The reaction by which the hydrocarbon compounds are converted successively to others relatively poorer in hydrogen is believed to be due to the reaction of the hydrocarbon andthe ferrous oxide producing metallic iron and nascent hydrogen which nascent hydrogen combines instantly-with the CO and, as stated above, the gaseous product resulting from thel present process is substantially free of hydrogen, whereas that of the process described in such patent contained a large proportion of uncombined hydrogen and had a rate of flame propagation so high as to prevent its use as a substitute propagation, such as natural gas.

What I claim is: l

1. The process of converting hydrocarbons of -the oleflnic series into hydrocarbons of the aromatic series and low-boiling-point alcohols which comprises successive dehydrogenation of said olefinic hydrocarbons in the vapor phase by reacting them, at substantially atmospheric pressure and at a temperature of about 1100 F. to about 1300 F., with steam in an amount equal Ito about 10% up to 30% of that of such olefinic vapors and with carbon monoxide in an amount approximately equal to the combined amounts of such vapors and steam in the presence of finely divided iron.

2. The process of converting hydrocarbons of the olefinic series containing up to sixteen carbon atomsginto hydrocarbons of the aromatic series and low-boiling-point alcohols which comprises mixing said hydrocarbons in vapor form at substantially atmospheric pressure and at a temperature of about 1100 F. to about 1300 F, with 'steam in an amount vequal to about 10% up to 30% of that of the olcnic vapors and with carbon monoxide in an amount approximately l equal to the combined amounts of the vapors and steam, in the presence of finely divided iron, formaldehyde and methanol being formed as successively hydrogenated products of the carbon monoxide by the reactionof nascent hydrogen,

and the olenic hydrocarbon compounds being successively dehydrogenated.

' ALEXANDER S. RAMAGE. 

